Misplaced Pages

#800199

134-600: The first use of searchlights using carbon arc technology occurred during the Siege of Paris during the Franco-Prussian War . The Royal Navy used searchlights in 1882 to dazzle and prevent Egyptian forces from manning artillery batteries at Alexandria . Later that same year, the French and British forces landed troops under searchlights. By 1907 the value of searchlights had become widely recognized. One recent use

268-677: A barrage placed across the Seine, and select approaches to the city laid with electrically-triggered mines. Forests and houses were cleared to improve the firing sight lines, roads were torn up, and railroad and road entrances to the city blocked. The Paris Catacombs were sealed off, along with certain quarries and excavations outside the city to deny an entry-point to the Prussians. The authorities in Paris also attended to provisions and took steps to stockpile cereals, salted meat, and preserves for

402-511: A force multiplier , allowing the husbanding of resources, both human and material, and only needing to scramble when attack was imminent. This greatly reduced pilot and aircraft fatigue. Very early in the battle, the Luftwaffe made a series of small but effective raids on several stations, including Ventnor , but they were repaired quickly. In the meantime, the operators broadcast radar-like signals from neighbouring stations in order to fool

536-487: A considerably higher figure of around 150,000 official and 1 million private communications, but this figure is arrived at by counting all copies of each message.) Late in the siege, William I was proclaimed German Emperor on 18 January 1871 at the Palace of Versailles . The kingdoms of Bavaria , Württemberg , and Saxony , the states of Baden and Hesse , and the free cities of Hamburg and Bremen were unified with

670-522: A crucial difference, as from their previous position the guns were only capable of reaching the fringes of the city. The first shells fell on the Left Bank that same day. Prussian artillerymen aimed their guns at the highest angles possible and increased the charges to obtain unprecedented ranges. Even so, although shells reached the Pont Notre-Dame and the Île Saint-Louis , none made it to

804-505: A demonstration in which operators were attempting to locate an "attacking" bomber, he noticed that the primary problem was not technological, but information management and interpretation. Following Watson-Watt's advice, by early 1940, the RAF had built up a layered control organization that efficiently passed information along the chain of command, and was able to track large numbers of aircraft and direct interceptors to them. Immediately after

938-618: A development project was started in great secrecy on the Orford Ness Peninsula in Suffolk . E. G. Bowen was responsible for developing the pulsed transmitter. On 17 June 1935, the research apparatus successfully detected an aircraft at a distance of 17 miles. In August, A. P. Rowe , representing the Tizard Committee, suggested the technology be code-named RDF, meaning Range and Direction Finding . In March 1936,

1072-510: A hospital), leading some to believe that the Prussians were deliberately targeting hospitals. Moltke, in response to a complaint on this matter from Trochu, responded that he hoped to soon move the artillery closer so that his gunners could better identify the Red Cross flags. About 400 perished or were wounded by the bombardment which, "had little effect on the spirit of resistance in Paris." Delescluze declared, "The Frenchmen of 1870 are

1206-452: A major advance in radar capability. The resulting magnetron was a small device that generated high-power microwave frequencies and allowed the development of practical centimetric radar that operated in the SHF radio frequency band from 3 to 30  GHz (wavelengths of 10 to 1 cm). Centimetric radar enables the detection of much smaller objects and the use of much smaller antennas than

1340-527: A mixer for the receiver were essential. These were targeted developments, the former by R W Sutton who developed the NR89 reflex klystron , or "Sutton tube". The latter by H W B Skinner who developed the 'cat's whisker' crystal. At the end of 1939 when the decision was made to develop 10 cm radar, there were no suitable active devices available - no high power magnetron, no reflex klystron, no proven microwave crystal mixer, and no TR cell. By mid-1941, Type 271,

1474-484: A new army and convince neutral powers to enter the war against Prussia. To Bismarck, Paris was the key to breaking the power of the intransigent republican leaders of France, ending the war in a timely manner, and securing peace terms favourable to Prussia. Moltke was also worried that insufficient winter supplies were reaching the German armies investing the city, as diseases such as tuberculosis were breaking out amongst

SECTION 10

#1732790609801

1608-454: A new one led by themselves, but they could not come to an agreement. In the meantime, battalions of loyal National Guards led by Jules Ferry and a detachment of Mobiles headed by the Prefect of Police, Edmond Adam, prepared to retake the building. Negotiations between the two sides concluded with a peaceful evacuation of the building by the insurgents early in the morning of November 1, and

1742-485: A passing airplane. This was officially reported by Taylor. Hyland, Taylor, and Young were granted a patent (U.S. No. 1981884, 1934) for a "System for detecting objects by radio". It was recognized that detection also needed range measurement, and funding was provided for a pulsed transmitter. This was assigned to a team led by Robert M. Page , and in December 1934, a breadboard apparatus successfully detected an aircraft at

1876-637: A project in Doppler-beat detection. Following Page's success with pulse-transmission, the SCL soon followed in this area. In 1936, Paul E. Watson developed a pulsed system that on December 14 detected aircraft flying in New York City airspace at ranges up to seven miles. By 1938, this had evolved into the Army's first Radio Position Finding (RPF) set, designated SCR-268 , Signal Corps Radio , to disguise

2010-474: A radio-based detection apparatus that was not further pursued by the Army. When war started and Air Ministry activities were relocated to Dundee , the Army detachment became part of a new developmental centre at Christchurch in Dorset . John D. Cockcroft , a physicist from Cambridge University , who was awarded a Nobel Prize after the war for work in nuclear physics, became Director. With its greater remit,

2144-452: A range of 15 miles. Types 282 and Type 285 were used with Bofors 40 mm guns . Type 283 and Type 284 were other 50-cm gunnery director systems. Type 289 was developed based upon Dutch pre-war radar technology and used a Yagi-antenna. With an improved RDF design it controlled Bofors 40 mm anti-aircraft guns (see Electric listening device ). The critical problem of submarine detection required RDF systems operating at higher frequencies than

2278-527: A range of one mile. The Navy, however, ignored further development, and it was not until January 1939, that their first prototype system, the 200-MHz (1.5-m) XAF , was tested at sea. The Navy coined the acronym RAdio Detection And Ranging (RADAR), and in late 1940, ordered this to be exclusively used. Taylor's 1930 report had been passed on to the U.S. Army's Signal Corps Laboratories (SCL). Here, William R. Blair had projects underway in detecting aircraft from thermal radiation and sound ranging, and started

2412-667: A regular mail service was established, with a rate of 20 centimes per letter. Two workshops to manufacture balloons were set up, one under the direction of Nadar in the Elysée-Montmartre dance-hall (later moved to the Gare du Nord ), and the other under the direction of Godard in the Gare d'Orleans . Around 66 balloon flights were made, including one that accidentally set a world distance record by ending up in Norway. The vast majority of these succeeded: only five were captured by

2546-658: A successful programme, started in 1936 by Edward George Bowen , developed a miniaturized RDF system suitable for aircraft, the on-board aircraft interception radar (AI) set (Watson-Watt called the CH sets the RDF-1 and the AI the RDF-2A). Initial AI sets were first made available to the RAF in 1939 and fitted to Bristol Blenheim aircraft (replaced quickly by Bristol Beaufighters ). These measures greatly increased Luftwaffe loss rates. Later in

2680-524: A surfaced submarine at 13 miles range. At Portsmouth, the team continued development, fitting antennas behind cylindrical parabolas (called "cheese" antennas) to generate a narrow beam that maintained contact as the ship rolled. Designated Type 271 radar , the set was tested in March 1941, detecting the periscope of a submerged submarine at almost a mile. The set was deployed in August 1941, just 12 months after

2814-449: A useful addition to the evolution of radar. This slow-to-fade display tube was used by air traffic controllers from the very beginning of radar. The Luftwaffe took to avoiding intercepting fighters by flying at night and in bad weather. Although the RAF control stations were aware of the location of the bombers, there was little they could do about them unless fighter pilots made visual contact. This problem had already been foreseen, and

SECTION 20

#1732790609801

2948-484: The 2022 Russian invasion of Ukraine a searchlight has been used for anti-aircraft warfare . Today, searchlights are used in advertising , fairs , festivals and other public events. Their use was once common for movie premieres ; the waving searchlight beams can still be seen as a design element in the logos of 20th Century Studios and the Fox television network . The world's most powerful searchlight today beams from

3082-465: The Battle of Britain , and was critical in enabling the RAF to defeat the much larger Luftwaffe forces. Whereas the Luftwaffe relied on, often out of date, reconnaissance data and fighter sweeps, the RAF knew with a high degree of accuracy Luftwaffe formation strengths and intended targets. The sector stations were able to send the required number of interceptors, often only in small numbers. CH acted as

3216-748: The GL3B sets were manufactured, it was the American version that was most numerous in the defense of London during the V-1 attacks. The Experimental Department of His Majesty's Signal School (HMSS) had been present at early demonstrations of the work conducted at Orfordness and Bawdsey Manor. Located at Portsmouth in Hampshire , the Experimental Department had an independent capability for developing wireless valves (vacuum tubes), and had provided

3350-602: The Hawker Hurricane . This never proved very successful, as the light made the emitting aircraft a very big target for rear gunners, who would simply have to shoot into the light and be guaranteed to hit something eventually. During the Battle of the North Atlantic , RAF aircraft such as the Vickers Wellington were assigned to patrol for surfaced German U-boats at night, when they would be on

3484-727: The North German Confederation to create the German Empire . The preliminary peace treaty was signed at Versailles, and the final peace treaty, the Treaty of Frankfurt , was signed on 10 May 1871. Otto von Bismarck was able to secure Alsace-Lorraine as part of the German Empire. The continued presence of German troops outside the city angered Parisians. Further resentment arose against the French government, and in March 1871 Parisian workers and members of

3618-617: The Prussian Guard at Le Bourget without orders, and took the town. The Guard actually had little interest in recapturing their positions at Le Bourget, but Crown Prince Albert ordered the city retaken anyway. In the Battle of Le Bourget the Prussian Guards succeeded in retaking the city and captured 1,200 French soldiers. Upon hearing of the French surrender at Metz and the defeat at Le Bourget, morale in Paris began to sink. The people of Paris were beginning to suffer from

3752-483: The Russo-Japanese War from 1904–05. Searchlights were installed on most naval capital ships from the late 19th century through WWII , both for tracking small, close-in targets such as torpedo boats , and for engaging enemy units in nighttime gun battles. The Imperial Japanese Navy especially was known for its intensive development of nighttime naval combat tactics and extensive training. The War in

3886-665: The Second World War . Controlled by sound locators and radars, searchlights could track bombers, indicating targets to anti-aircraft guns and night fighters and dazzling crews. Searchlights were occasionally used tactically in ground battles. One notable occasion was the Red Army use of searchlights during the Battle of the Seelow Heights in April 1945. 143 searchlights were directed at the German defence force, with

4020-525: The Seine . On 30 September Vinoy attacked Chevilly with 20,000 soldiers and was soundly repulsed by the 3rd Army. Then on 13 October the II Royal Bavarian Corps was driven from Châtillon but the French were forced to retire in face of Prussian artillery. General Carey de Bellemare commanded the strongest fortress north of Paris at Saint Denis . On 29 October de Bellemare attacked

4154-505: The Soviet Union . Operational research found that anti-aircraft guns using GL averaged 4,100 rounds fired per hit, compared with about 20,000 rounds for predicted fire using a conventional director . In early 1938, Alan Butement began the development of a Coastal Defence ( CD ) system that involved some of the most advanced features in the evolving technology. The 200 MHz transmitter and receiver already being developed for

Searchlight - Misplaced Pages Continue

4288-512: The Sperry Company . These were mostly of 60 inch (152.4 cm) diameter with rhodium plated parabolic mirror, reflecting a carbon arc discharge. Peak output was 800,000,000 candela . It was powered by a 15 kW generator and had an effective beam visibility of 28 to 35 miles (45 to 56 km) in clear low humidity. The searchlight also found a niche for use by night fighters and anti-submarine warfare aircraft. The Turbinlite

4422-748: The duplexers for VHF were destroyed by the new higher-powered transmitter. This problem was solved in early 1941 by the transmit-receive (T-R) switch developed at the Clarendon Laboratory of Oxford University , allowing a pulse transmitter and receiver to share the same antenna without affecting the receiver. The combination of magnetron, T-R switch, small antenna and high resolution allowed small, powerful radars to be installed in aircraft. Maritime patrol aircraft could detect objects as small as submarine periscopes , allowing aircraft to track and attack submerged submarines, where before only surfaced submarines could be detected. However, according to

4556-409: The investment of the city. Crown Prince Albert's army closed in on Paris from the north unopposed, while Crown Prince Frederick moved in from the south. On 17 September a force under Vinoy attacked Frederick's army near Villeneuve-Saint-Georges in an effort to save a supply depot there, but it was eventually driven back by artillery fire. The railroad to Orléans was cut, and on the 18th Versailles

4690-556: The resonant-cavity magnetron , capable of producing microwave power in the kilowatt range, opening the path to second-generation radar systems. After the Fall of France , Britain realised that the manufacturing capabilities of the United States were vital to success in the war; thus, although America was not yet a belligerent, Prime Minister Winston Churchill directed that Britain's technological secrets be shared in exchange for

4824-551: The AI and ASV sets of the Air Defence were used, but, since the CD would not be airborne, more power and a much larger antenna were possible. Transmitter power was increased to 150 kW. A dipole array 10 feet (3.0 m) high and 24 feet (7.3 m) wide, was developed, giving much narrower beams and higher gain. This "broadside" array was rotated 1.5 revolutions per minute, sweeping a field covering 360 degrees. Lobe switching

4958-720: The British Army in Malta and Egypt in 1939–40. Seventeen sets were sent to France with the British Expeditionary Force ; while most were destroyed at the Dunkirk evacuation in late May 1940, a few were captured intact, giving the Germans an opportunity to examine British RDF kit. An improved version, GL Mk. II , was used throughout the war; some 1,700 sets were put into service, including over 200 supplied to

5092-651: The British were without peer. The result of the Tizard Mission was a major step forward in the evolution of radar in the United States. Although both the NRL and SCL had experimented with 10–cm transmitters, they were stymied by insufficient transmitter power. The cavity magnetron was the answer the U.S. was looking for, and it led to the creation of the MIT Radiation Laboratory (Rad Lab). Before

5226-719: The Commune. The King in Yellow , a short story collection by Robert W. Chambers , published in 1895, includes a story titled "The Street of the First Shell" which takes place over a few days of the siege. 48°51′24″N 2°21′06″E  /  48.8566°N 2.3518°E  / 48.8566; 2.3518 Radar in World War II Radar in World War II greatly influenced many important aspects of

5360-611: The Council for the Defence of Paris proposing the use of balloons for communication with the outside world: a similar proposal had also been made by the balloonist Eugène Godard . The first balloon launch was carried out on 23 September, using the Neptune , and carried 125 kg (276 lb) of mail in addition to the pilot. After a three-hour flight it landed at Craconville 83 km (52 mi) from Paris. Following this success

5494-527: The Germans fired some 12,000 shells into the city over 23 nights in an attempt to break Parisian morale. The attack on the city itself was preceded by the bombardment of the southern forts from the Châtillon Heights on 5 January. That day, the guns of forts Issy and Vanves were silenced by a relentless barrage, allowing the Prussian artillery to be moved up to 750 yards closer to Paris. This made

Searchlight - Misplaced Pages Continue

5628-401: The Germans that coverage continued. The Germans' attacks were sporadic and short-lived. The German High Command apparently never understood the importance of radar to the RAF's efforts, or they would have assigned these stations a much higher priority. Greater disruption was caused by destroying the teletype and landline links of the vulnerable above-ground control huts and the power cables to

5762-545: The Government of National Defense would conclude armistice negotiations with the North German Confederation on 28 January 1871. While the armistice led to food shipments being immediately permitted into the city, the capture of their capital city and the disaster of the war itself would have a long-lasting impact on the French populace, Franco-German relations , and Europe as a whole. French defeat in

5896-692: The National Guard rebelled and established the Paris Commune , a radical socialist government, which lasted through late May of that year. Empires of Sand by David W. Ball ( Bantam Dell , 1999) is a novel in two parts, the first of which is set during the Franco-Prussian war, more particularly the Siege of Paris during the winter of 1870–71. Key elements of the siege, including the hot-air balloons used for reconnaissance and messages,

6030-666: The Pacific saw a number of nocturnal engagements fought by searchlight, particularly the Battle of Savo Sound at Guadalcanal. Although searchlights remained in use throughout the war, the newly developed radar proved to be a far more effective locating device, and Japanese radar development lagged far behind that of the US. Searchlights were first used in the First World War to create "artificial moonlight" to enhance opportunities for night attacks by reflecting searchlight beams off

6164-634: The Prussians at Champigny , Créteil and Villiers . In what became known as the Battle of Villiers the French succeeded in capturing and holding a position at Créteil and Champigny. By 2 December the XIII (Royal Württemberg) Corps had driven Ducrot back into the defenses and the battle was over by 3 December. On 21 December, French forces attempted another breakout at Le Bourget, in the hopes of meeting up with General Louis Faidherbe 's army. Trochu and Ducrot had been encouraged by Faidherbe's capture on 9 December of Ham , around 65 miles from Paris. The weather

6298-501: The Prussians, and three went missing, presumably coming down in the Atlantic or Irish Sea. The number of letters carried has been estimated at around 2.5 million. Some balloons also carried passengers in addition to the cargo of mail, most notably Léon Gambetta , the minister for War in the new government, who was flown out of Paris on 7 October. The balloons also carried homing pigeons out of Paris to be used for pigeon post . This

6432-692: The RDF research and development effort was moved to the Bawdsey Research Station located at Bawdsey Manor in Suffolk. While this operation was under the Air Ministry, the Army and Navy became involved and soon initiated their own programs. At Bawdsey, engineers and scientists evolved the RDF technology, but Watson-Watt, the head of the team, turned from the technical side to developing a practical machine/human user interface. After watching

6566-596: The Radio Research Station, Slough, was asked to investigate a radio-based "death ray". In response, Watson-Watt and his scientific assistant, Arnold F. Wilkins , replied that it might be more practical to use radio to detect and track enemy aircraft. On 26 February 1935, a preliminary test, commonly called the Daventry Experiment , showed that radio signals reflected from an aircraft could be detected. Research funds were quickly allocated, and

6700-427: The Right Bank. Up to 20,000 refugees fled the Left Bank, putting a further strain on the already overburdened food supplies of the Right Bank arrondissements . The domes of the Panthéon and the Invalides were frequent targets of the artillerymen, and the vicinities of those buildings were particularly damaged as a result. Shells also struck the Salpetrière Hospital and the Théâtre de l'Odéon (then being used as

6834-440: The Seine, these were all unsuccessful. The pigeons were taken to their base, first at Tours and later at Poitiers , and when they had been fed and rested were ready for the return journey. Tours lies some 200 km (120 mi) from Paris and Poitiers some 300 km (190 mi) distant. Before release, they were loaded with their dispatches. Initially the pigeon post was only used for official communications but on 4 November

SECTION 50

#1732790609801

6968-440: The TRU had two vans for the electronic equipment and a generator van; it used a 105-ft portable tower to support a transmitting antenna and two receiving antennas. A prototype was tested in October 1937, detecting aircraft at 60-miles range; production of 400 sets designated GL Mk. I began in June 1938. The Air Ministry adopted some of these sets to augment the CH network in case of enemy damage. GL Mk. I sets were used overseas by

7102-404: The U.S. Navy Aircraft Radio Laboratory, noticed that a ship crossing the transmission path of a radio link produced a slow fading in and out of the signal. They reported this as a Doppler-beat interference with potential for detecting the passing of a vessel, but it was not pursued. In 1930, Lawrence A. Hyland . working for Taylor at the Naval Research Laboratory (NRL) noted the same effect from

7236-417: The United States, wartime radars were also developed and used by Australia , Canada , France , Italy , Japan , New Zealand , South Africa , the Soviet Union , and Sweden . Research leading to RDF technology in the United Kingdom was begun by Sir Henry Tizard 's Aeronautical Research Committee in early 1935, responding to the urgent need to anticipate German bomber attacks. Robert A. Watson-Watt at

7370-475: The aim of temporarily blinding them during a Soviet offensive, begun with the largest artillery bombardment the world had ever seen until that point. However, the morning fog diffused the light and silhouetted the attacking Soviet forces, making them clearly visible to the Germans. The Soviets suffered heavy losses as a result and were forced to delay their invasion of the city. Second World War-era searchlights include models manufactured by General Electric and by

7504-405: The antenna was rotated mechanically, followed by the display on the operator's console. That is, instead of a single line across the bottom of the display from left to right, the line was rotated around the screen at the same speed as the antenna was turning. The result was a 2-D display of the air space around the station with the operator in the middle, with all the aircraft appearing as dots in

7638-443: The besieged city could reach the rest of France. The use of balloons to carry mail was first proposed by the photographer and balloonist Felix Nadar , who had established the grandiosely titled No. 1 Compagnie des Aérostatiers , with a single balloon, the Neptune , at its disposal, to perform tethered ascents for observation purposes. However the Prussian encirclement of the city made this pointless, and on 17 September Nadar wrote to

7772-401: The besieging soldiers. In addition, the siege operations competed with the demands of the ongoing Loire Campaign against the remaining French field armies. Air medical transport is often stated to have first occurred in 1870 during the siege of Paris when 160 wounded French soldiers were evacuated from the city by hot-air balloon, but this myth has been definitively disproven by full review of

7906-454: The bottom of the screen – would give target range. By rotating the receiver goniometer connected to the antennas, the operator could estimate the direction to the target (this was the reason for the cross shaped antennas), while the height of the vertical displacement indicated formation size. By comparing the strengths returned from the various antennas up the tower, altitude could be gauged with some accuracy. CH proved highly effective during

8040-488: The bottoms of clouds, a practice which continued in the Second World War . The term "artificial moonlight" was used to distinguish illumination provided by searchlights from that provided by natural moonlight, which was referred to as "movement light" in night-time manoeuvers. Searchlights were also heavily used in the defense of the UK against German nighttime bombing raids using Zeppelins . Searchlights were used extensively in defense against nighttime bomber raids during

8174-404: The capitulation became public. Bismarck's advice was to "provoke an uprising, then, while you still have an army with which to suppress it". The final terms agreed on were that the French regular troops (less one division) would be disarmed, Paris would pay an indemnity of two hundred million francs, and the fortifications around the perimeter of the city would be surrendered. In return the armistice

SECTION 60

#1732790609801

8308-407: The capture of Napoleon III, the Second French Empire collapsed and the Third French Republic was declared, provisionally led by the Government of National Defense . Despite German forces reaching and besieging Paris by 19 September 1870, the new French government advocated for the continuation of the war, leading to over four more months of fighting, during which Paris was continuously besieged. With

8442-419: The city by storm, and the French could then rely on the city's defenses. These consisted of the 33 km (21 mi) Thiers wall and a ring of sixteen detached forts , all of which had been built in the 1840s. Moltke never had any intention of attacking the city and this became clear shortly after the siege began. Trochu changed his plan and allowed Vinoy to make a demonstration against the Prussians west of

8576-430: The city for much of the siege. He also led the way in providing humanitarian relief to foreign nationals, including ethnic Germans. As the siege wore on, food supplies dwindled, and prices skyrocketed. The authorities instituted price controls on certain staple foods at the beginning of the siege, but these were rendered ineffective by a lack of enforcement and the rampant black market in the city. Until mid-October there

8710-489: The city fully encircled, the Parisian garrison attempted three unsuccessful break-out attempts and German forces began a relatively ineffectual artillery bombardment campaign of the city in January 1871. In response to the poor results of the artillery bombardment, the Prussians brought forth large-caliber Krupp heavy siege artillery to attack the city beginning 25 January 1871. With the renewed artillery attack and an increasingly starving and ill Parisian population and garrison,

8844-404: The city pointless, but the German high command, headed by the king of Prussia, turned down the proposal on the insistence of General von Blumenthal, on the grounds that a bombardment would affect civilians, violate the rules of engagement, and turn the opinion of third parties against the Germans, without speeding up the final victory. It was also contended that a quick French surrender would leave

8978-508: The city, and butchers began offering dog and cat meat . People also turned to rats for meat, although the numbers of rats consumed was relatively low due to fear of disease, and the expense of preparing rat meat in order to make it edible. Once the supply of those animals ran low, the citizens of Paris turned on the zoo animals residing at Jardin des plantes . Even Castor and Pollux , the only pair of elephants in Paris, were slaughtered for their meat . A Latin Quarter menu contemporary with

9112-423: The conflict. This revolutionary new technology of radio-based detection and tracking was used by both the Allies and Axis powers in World War II , which had evolved independently in a number of nations during the mid 1930s. At the outbreak of war in September 1939, both the United Kingdom and Germany had functioning radar systems. In the UK, it was called RDF, Range and Direction Finding , while in Germany

9246-407: The crew and passenger records of each balloon which left Paris during the siege. During the siege, the only head of diplomatic mission from a major power who remained in Paris was United States Minister to France , Elihu B. Washburne . As a representative of a neutral country, Washburne was able to play a unique role in the conflict, becoming one of the few channels of communication into and out of

9380-475: The development of the GL3B . All of the equipment, including the power generator, was contained in a protected trailer, topped with two 6-foot dish transmitting and receiving antennas on a rotating base, as the transmit-receive (T-R) switch allowing a single antenna to perform both functions had not yet been perfected. Similar microwave gun-laying systems were being developed in Canada (the GL3C ) and in America (eventually designated SCR-584 ). Although about 400 of

9514-426: The earlier, lower frequency radars. A radar with a wavelength of 2 meters (VHF band, 150 MHz) cannot detect objects that are much smaller than 2 meters and requires an antenna whose size is on the order of 2 meters (an awkward size for use on aircraft). In contrast, a radar with a 10 cm wavelength can detect objects 10 cm in size with a reasonably sized antenna. In addition a tuneable local oscillator and

9648-429: The east of the city, to be withdrawn from there when France paid the agreed war indemnity . While Parisians scrubbed the streets "polluted" by the triumphal entry, no serious incidents occurred during the short and symbolic occupation of the city. This was in part because the Germans had avoided areas such as Belleville , where hostility was reportedly high. Balloon mail was the only means by which communications from

9782-464: The effects of the German blockade. On 31 October, the day the government confirmed the surrender of Metz and one day after Le Bourget's recapture was announced, an angry mob besieged and invaded the Hôtel de Ville , taking Trochu and his cabinet hostage. The insurgent leaders ( Gustave Flourens , Louis Charles Delescluze , Louis Auguste Blanqui among them) attempted to depose Trochu's government and form

9916-416: The even higher-frequency American-created H2X , allowed new tactics in the strategic bombing campaign . Centimetric gun-laying radars were much more accurate than older technology; radar improved Allied naval gunnery and, together with the proximity fuze , made anti-aircraft guns much more effective. The two new systems used by anti-aircraft batteries are credited with destroying many V-1 flying bombs in

10050-576: The exchange began, the British were surprised to learn of the development of the U.S. Navy's pulse radar system, the CXAM , which was found to be very similar in capability to their Chain Home technology. Although the U.S. had developed pulsed radar independently of the British, there were serious weaknesses in America's efforts, especially the lack of integration of radar into a unified air defense system. Here,

10184-571: The existing Chain Home. Consequently, CD was also adopted by the RAF to augment the CH stations; in this role, it was designated Chain Home Low ( CHL ). When the cavity magnetron became practicable, the ADEE co-operated with TRE in utilising it in an experimental 20 cm GL set. This was first tested and found to be too fragile for army field use. The ADEE became the ADRDE in early 1941, and started

10318-513: The existing sets because of a submarine's smaller physical size than most other vessels. When the first cavity magnetron was delivered to the TRE, a demonstration breadboard was built and demonstrated to the Admiralty. In early November 1940, a team from Portsmouth under S. E. A. Landale was set up to develop a 10-cm surface-warning set for shipboard use. In December, an experimental apparatus tracked

10452-659: The facility became the Air Defence Research and Development Establishment (ADRDE) in mid-1941. A year later, the ADRDE relocated to Great Malvern , in Worcestershire . In 1944, this was redesignated the Radar Research and Development Establishment (RRDE). While at Bawdsey, the Army detachment developed a Gun Laying ("GL") system termed Transportable Radio Unit ( TRU ). Pollard was project leader. Operating at 60 MHz (6-m) with 50-kW power,

10586-439: The field-marshal to consult with Bismarck for all future operations. Bismarck immediately ordered the city to be bombarded with large-caliber Krupp siege guns. This prompted the city's surrender on 28 January 1871. Secret armistice discussions began on January 23, 1871 and continued at Versailles between Jules Favre and Bismarck until the 27th. On the French side there was concern that the National Guard would rebel when news of

10720-413: The first British convoy of food at Les Halles sparked a riot and pillaging, "while for seven hours the police seemed powerless to intervene". Thirty thousand Prussian, Bavarian and Saxon troops held a brief victory parade in Paris on March 1, 1871 and Bismarck honored the armistice by sending trainloads of food into the city. The German troops departed after two days to take up temporary encampments to

10854-501: The first Naval S-band radar, was in operational use. The cavity magnetron was perhaps the single most important invention in the history of radar. In the Tizard Mission during September 1940, it was given free to the U.S., along with other inventions, such as jet technology, in exchange for American R&D and production facilities; the British urgently needed to produce the magnetron in large quantities. Edward George Bowen

10988-453: The first apparatus was demonstrated. On November 16, the first German submarine was sunk after being detected by a Type 271. The initial Type 271 primarily found service on smaller vessels . At ASE Witley, this set was modified to become Type 272 and Type 273 for larger vessels. Using larger reflectors, the Type 273 also effectively detected low-flying aircraft, with a range up to 30 miles. This

11122-495: The foodstuffs, at the beginning of February the London Relief Committee donated "nearly 10,000 tons of flour, 450 tons of rice, 900 tons of biscuits, 360 tons of fish, and nearly 4,000 tons of fuel, with about 7,000 head of livestock". The United States sent around $ 2 million worth of food, but much of it was held up at the port of Le Havre because of a shortage of workers for unloading the ships. The arrival of

11256-498: The government announced that members of the public could send messages, these being limited to twenty words at a charge of 50 centimes per word. These were then copied onto sheets of cardboard and photographed by a M. Barreswille, a photographer based in Tours. Each sheet contained 150 messages and was reproduced as a print about 40 by 55 mm (1.6 by 2.2 in) in size: each pigeon could carry nine of these. The photographic process

11390-576: The governor and commander-in-chief of the city's defenses, General Louis Jules Trochu , assembled a force of 60,000 regular soldiers who had managed to escape from Sedan under Joseph Vinoy or who were gathered from depot troops. Together with 90,000 Mobiles (Territorials), a brigade of 13,000 naval seamen and 350,000 National Guards , the potential defenders of Paris totaled around 513,000. The compulsorily enrolled National Guards were, however, untrained. They had 2,150 cannon plus 350 in reserve, and 8,000,000 kg of gunpowder. The French had expected

11524-683: The ground without "seeing" the reflection of the ground or water – known as clutter . Unlike the larger CH systems, the CHL broadcast antenna and receiver had to be rotated; this was done manually on a pedal-crank system by members of the WAAF until the system was motorised in 1941. Systems similar to CH were later adapted with a new display to produce the Ground-Controlled Intercept (GCI) stations in January 1941. In these systems,

11658-455: The late summer of 1944. During Air Ministry RDF development in Bawdsey, an Army detachment was attached to initiate its own projects. These programmes were for a Gun Laying (GL) system to assist aiming antiaircraft guns and searchlights and a Coastal Defense (CD) system for directing coastal artillery. The Army detachment included W. A. S. Butement and P. E. Pollard who, in 1930, demonstrated

11792-513: The latest reports on the history U.S. Navy periscope detection the first minimal possibilities for periscope detection appeared only during 50's and 60's and the problem was not completely solved even on the turn of the millennium. In addition, radar could detect the submarine at a much greater range than visual observation, not only in daylight but at night, when submarines had previously been able to surface and recharge their batteries safely. Centimetric contour mapping radars such as H2S , and

11926-475: The major RDF/radar equipment used by the Air Ministry is briefly described. All of the systems were given the official designation Air Ministry Experimental Station (AMES) plus a Type number; most of these are listed in this link. Shortly before the outbreak of World War II, several RDF (radar) stations in a system known as Chain Home (or CH ) were constructed along the South and East coasts of Britain, based on

12060-517: The masts than by attacking the open latticework towers themselves. To avoid the CH system, the Luftwaffe adopted other tactics. One was to approach the coastline at very low altitude. This had been anticipated and was countered to some degree with a series of shorter-range stations built right on the coast, known as Chain Home Low ( CHL ). These systems had been intended for naval gun-laying and known as Coastal Defence (CD), but their narrow beams also meant that they could sweep an area much closer to

12194-582: The most of anybody. Their husbands had the relative advantage of their 1.50 francs per day National Guard pay, "little enough of which reached their wives", and the fact that they were occupied, because "anyone who was occupied – even the National Guardsman warming himself in the bistro while his wife queued for food – had a better chance of survival." Parisians turned first to horses in early-October to supplement their dwindling supplies of fresh meat. By mid-November, fresh meat had truly run out in

12328-466: The name Funkmeß (radio-measuring) was used, with apparatuses called Funkmessgerät (radio measuring device). By the time of the Battle of Britain in mid-1940, the Royal Air Force (RAF) had fully integrated RDF as part of the national air defence. In the United States, the technology was demonstrated during December 1934. However, it was only when war became likely that the U.S. recognized

12462-599: The needed capabilities. In the summer of 1940, the Tizard Mission visited the United States. The cavity magnetron was demonstrated to Americans at RCA, Bell Labs, etc. It was 100 times more powerful than anything they had seen. Bell Labs was able to duplicate the performance, and the Radiation Laboratory at MIT was established to develop microwave radars. The magnetron was later described by American military scientists as "the most valuable cargo ever brought to our shores". In addition to Britain, Germany, and

12596-503: The new French armies undefeated and allow France to renew the war shortly after. The new French armies would have to be annihilated first, and Paris would have to be starved into surrender. Trochu had little faith in the ability of the National Guards, which made up half the force defending the city. So instead of making any significant attempt to prevent the investment by the Germans, Trochu hoped that Moltke would attempt to take

12730-526: The population. Much of this was stored in the Opéra Garnier . The Bois de Boulogne and Luxembourg Gardens were packed with livestock – the former received some 250,000 sheep and 40,000 oxen. The government believed it had enough flour and wheat to last for 80 days, more than enough based on the assumption, then prevalent, that the siege would be relatively brief. The Prussian armies quickly reached Paris, and on 15 September Moltke issued orders for

12864-626: The potential of the new technology, and began the development of ship- and land-based systems. The U.S. Navy fielded the first of these in early 1940, and a year later by the U.S. Army . The acronym RADAR (for Radio Detection And Ranging) was coined by the U.S. Navy in 1940, and the term "radar" became widely used. While the benefits of operating in the microwave portion of the radio spectrum were known, transmitters for generating microwave signals of sufficient power were unavailable; thus, all early radar systems operated at lower frequencies (e.g., HF or VHF ). In February 1940, Great Britain developed

12998-423: The proper location in space. Called plan position indicators (PPI), these simplified the amount of work needed to track a target on the operator's part. Philo Taylor Farnsworth refined a version of his picture tube ( cathode ray tube , or CRT) and called it an "Iatron". It could store an image for milliseconds to minutes (even hours). One version that kept an image alive about a second before fading, proved to be

13132-709: The pulse width. With steerable antennas, it was also used for Gun Control. This was first used in combat in March 1941 with considerable success. Type 281B used a common transmitting and receiving antenna. The Type 281 , including the B-version, was the most battle-tested metric system of the Royal Navy throughout the war. In 1938, John F. Coales began the development of 600-MHz (50-cm) equipment. The higher frequency allowed narrower beams (needed for air search) and antennas more suitable for shipboard use. The first 50-cm set

13266-454: The questioning of France's status as the dominant power of continental Europe. With a declaration of war by the French parliament on 16 July 1870, Imperial France soon faced a series of defeats at German hands over the following months, leading to the Battle of Sedan , which, on 2 September 1870, saw a decisive defeat of French forces and the capture of the French emperor, Napoleon III . With

13400-424: The radar generated strong returns from ships and docks. This was due to the vertical sides of the objects, which formed excellent partial corner reflectors , allowing detection at several miles range. The team focussed on this application for much of 1938. The Air-to-surface-vessel (ASV) Mark I, using electronics similar to those of the AI sets, was the first aircraft-carried radar to enter service, in early 1940. It

13534-430: The release of the hostages. Despite promising no reprisals against the revolutionaries, the Government was swift to arrest and imprison 22 of the leaders, which further embittered the left-wing of Paris. Hoping to boost morale on 30 November Trochu launched the largest attack from Paris even though he had little hope of achieving a breakthrough. Nevertheless, he sent Auguste-Alexandre Ducrot with 80,000 soldiers against

13668-476: The rooftops of several attractions in Fantasyland . Siege of Paris (1870-71) German victory [REDACTED]   North German Confederation (before 18 January 1871) [REDACTED]   Baden [REDACTED]   Bavaria [REDACTED]   Württemberg The siege of Paris took place from 19 September 1870 to 28 January 1871 and ended in the capture of the city by forces of

13802-529: The siege reads in part: The increasing hunger of the Parisians coincided with bitterly cold winter weather and a dire lack of fuel for heat. Coal gas , because of its essential use for the balloons, was strictly rationed and mostly replaced by oil. On November 25, oil itself was requisitioned. This left people reliant on increasingly scarce supplies of wood. By late-December, the inhabitants of working-class Belleville were so desperate for wood they had felled

13936-567: The siege, were primarily concerned with a methodical siege that would destroy the detached forts around the city and slowly strangle the defending forces with a minimum of German casualties. But as time wore on, there was growing concern that a prolonged war was placing too much strain on the German economy and that an extended siege would convince the French Government of National Defense that Prussia could still be beaten. A prolonged campaign would also allow France time to reconstitute

14070-681: The sons of those Gauls for whom battles were holidays." In actuality, the level of destruction fell short of what the Prussians had expected. The shells often caused little damage to the buildings they struck, and many fell in open spaces away from people. An English observer, Edwin Child, wrote that he "Became more and more convinced of the impossibility of effectually bombarding Paris, the houses being built of such solid blocks of stone that they could only be destroyed piecemeal. One bomb simply displaces one stone, in spite of their enormous weight..." On 25 January 1871, Wilhelm I overruled Moltke and ordered

14204-531: The street trees of their neighborhoods and were moving into the wealthier areas of western Paris, cutting down trees along the Champs Élysées and Avenue Foch . By January, 3,000–4,000 people were dying per week from the effects of cold and hunger. There were sharp rises in cases of smallpox , typhoid , and especially pneumonia . Typhoid came because the siege forced Parisians to turn to the Seine for much of their drinking water. In January, on Bismarck's advice,

14338-484: The successful model at Bawdsey. CH was a relatively simple system. The transmitting side comprised two 300-ft (90-m)-tall steel towers strung with a series of antennas between them. A second set of 240-ft (73-m)-tall wooden towers was used for reception, with a series of crossed antennas at various heights up to 215 ft (65 m). Most stations had more than one set of each antenna, tuned to operate at different frequencies . Typical CH operating parameters were: CH output

14472-493: The surface, charging their batteries . A large searchlight called a Leigh light was suspended from the bottom of the wing or fuselage , and would be used to illuminate the surfaced U-boat while it was being attacked with bombs and depth charges . The Leigh light was somewhat more successful than the Turbinlite, but in both cases the development of centimeter-wave radar proved to be the far more effective answer. During

14606-529: The technology. It operated at 200 MHz 1.5 m, with 7-kW peak power. The received signal was used to direct a searchlight . In Europe, the war with Germany had depleted the United Kingdom of resources. It was decided to give the UK's technical advances to the United States in exchange for access to related American secrets and manufacturing capabilities. In September 1940, the Tizard Mission began. When

14740-865: The top of the pyramid-shaped Luxor Hotel in Las Vegas . It concentrates about 13,650,000 lumens from 39 7kW xenon lamps into a beam of about 9,129,000,000 candela . Tribute in Light is an art installation that uses two columns of searchlights to represent the former Twin Towers of the World Trade Center , in remembrance of the September 11 attacks . It is produced annually in Lower Manhattan . Disney parks uses searchlights in their nighttime fireworks displays. They are installed on top of

14874-722: The tubes used by Bowden in the transmitter at Orford Ness. With excellent research facilities of its own, the Admiralty-based its RDF development at the HMSS. This remained in Portsmouth until 1942, when it was moved inland to safer locations at Witley and Haslemere in Surrey . These two operations became the Admiralty Signal Establishment (ASE). A few representative radars are described. Note that

15008-464: The tunnels beneath the city, the starvation and the cold, combine to render a vivid impression of war-time Paris before its surrender. The Old Wives' Tale by Arnold Bennett is a novel which follows the fortunes of two sisters, Constance and Sophia Baines. The latter runs away to make a disastrous marriage in France, where after being abandoned by her husband, she lives through the Siege of Paris and

15142-534: The type numbers are not sequential by date. The Royal Navy's first successful RDF was the Type 79Y Surface Warning , tested at sea in early 1938. John D. S. Rawlinson was the project director. This 43-MHz (7-m), 70-kW set used fixed transmitting and receiving antennas and had a range of 30 to 50 miles, depending on the antenna heights. By 1940, this became the Type 281 , increased in frequency to 85 MHz (3.5 m) and power to between 350 and 1,000 kW, depending on

15276-625: The various states of the North German Confederation , led by the Kingdom of Prussia . The siege was the culmination of the Franco-Prussian War , which saw the Second French Empire attempt to reassert its dominance over continental Europe by declaring war on the North German Confederation. The Prussian-dominated North German Confederation had recently emerged victorious in the Austro-Prussian War of 1866, which led to

15410-749: The war began in September 1939, the Air Ministry RDF development at Bawdsey was temporarily relocated to University College, Dundee in Scotland. A year later, the operation moved to near Worth Matravers in Dorset on the southern coast of England, and was named the Telecommunications Research Establishment (TRE). In a final move, the TRE relocated to Malvern College in Great Malvern . Some of

15544-411: The war to be fought mainly on German soil; it was not until the defeats at Spicheren and Frœschwiller that the authorities began to take serious action in organizing the defenses of Paris. A committee under the leadership of Marshal Vaillant was formed and given a budget of 12 million francs to strengthen the defenses. Barriers were put up around the city, 12,000 workers employed to dig earthworks,

15678-492: The war would directly lead to a victorious North German Confederation unifying with still-independent South German states and declaring the German Empire as well as a disgruntled and radicalized Parisian population taking control of Paris and forming the Paris Commune . As early as August 1870, the Prussian 3rd Army led by Crown Prince Frederick of Prussia (the future Frederick III, German Emperor ), had been marching towards Paris . A French force accompanied by Napoleon III

15812-502: The war, British Mosquito night intruder aircraft were fitted with AI Mk VIII and later derivatives, which with Serrate allowed them to track down German night fighters from their Lichtenstein signal emissions, as well as a device named Perfectos that tracked German IFF . As a countermeasure, the German night fighters employed Naxos ZR radar signal detectors. While testing the AI radars near Bawdsey Manor, Bowen's team noticed

15946-471: Was Type 282. With 25-kW output and a pair of Yagi antennas incorporating lobe switching, it was trialed in June 1939. This set detected low-flying aircraft at 2.5 miles and ships at 5 miles. In early 1940, 200 sets were manufactured. To use the Type 282 as a rangefinder for the main armament, an antenna with a large cylindrical parabolic reflector and 12 dipoles was used. This set was designated Type 285 and had

16080-439: Was a powerful searchlight mounted in the nose of an RAF Douglas Boston light bomber , converted into a night fighter to shoot down Luftwaffe night bombers . The aircraft would be directed in the general direction of the enemy by ground-based or metre-wave airborne radar, and the pilot would then switch on the Turbinlite, illuminating the enemy aircraft, which would then be shot down by accompanying RAF day fighters such as

16214-658: Was aimed at the Château of Buzenval in Rueil-Malmaison near the Prussian Headquarters, west of Paris. The crown prince easily repulsed the attack inflicting over 4,000 casualties while suffering just over 600. Trochu resigned as governor and left General Joseph Vinoy with 146,000 defenders. During the winter, tensions began to arise in the Prussian high command. Field-Marshal Helmuth von Moltke and General Leonhard, Count von Blumenthal , who commanded

16348-461: Was attached to the mission as the RDF lead. This led to the creation of the Radiation Laboratory (Rad Lab) based at MIT to further develop the device and usage. Half of the radars deployed during World War II were designed at the Rad Lab, including over 100 different systems costing US$ 1.5 billion. When the cavity magnetron was first developed, its use in microwave RDF sets was held up because

16482-483: Was deployed to aid the army encircled by Prussians at the Siege of Metz . This force was crushed at the Battle of Sedan , and the road to Paris was left open. Personally leading the Prussian forces, King William I of Prussia , along with his chief of staff Helmuth von Moltke , took the 3rd Army and the new Prussian Army of the Meuse under Albert, Crown Prince of Saxony , and marched on Paris virtually unopposed. In Paris,

16616-563: Was extended until February 19. Food supplies from the provinces, as well as shiploads from Britain and the United States, began to enter the starving city almost immediately. Britain sent ships from the Royal Navy loaded with Army food provisions, while private organizations like the Lord Mayor 's Relief Fund and the London Relief Committee made significant donations. According to the British representative responsible for distributing

16750-399: Was extremely cold, and the well-installed, well-concealed Prussian artillery inflicted heavy casualties on the advancing French. Soldiers camped overnight with no fuel for warmth, as the temperature fell to 7°F (−14°C). There were over 900 cases of frostbite , and 2,000 casualties on the French side. On the Prussian side, there were less than 500 dead. On 19 January a final breakout attempt

16884-433: Was further refined by René Dagron to allow more to be carried: Dagron, with his equipment, was flown out of Paris on 12 November in the aptly named Niépce , narrowly escaping capture by the Prussians. The photographic process allowed multiple copies of the messages to be sent, so that although only 57 of the 360 pigeons released reached Paris more than 60,000 of the 95,000 messages sent were delivered. (some sources give

17018-414: Was incorporated in the transmitting array, giving high directional accuracy. To analyze system capabilities, Butement formulated the first mathematical relationship that later became the well-known "radar range equation". Although initially intended for detecting and directing fire at surface vessels, early tests showed that the CD set had much better capabilities for detecting aircraft at low altitudes than

17152-419: Was no rationing of any kind, and afterwards only meat was subject to rationing (bread was rationed at the very end of the siege). There were also no attempts to limit hoarding and speculation. Many of the wealthier residents were well-placed to weather the siege since they had put aside stores of food before it began. Infant mortality soared because of the lack of fresh milk. Poor women and their children suffered

17286-404: Was quickly replaced by the improved Mark II, which included side-scanning antennas that allowed the aircraft to sweep twice the area in a single pass. The later ASV Mk. II had the power needed to detect submarines on the surface, eventually making such operations suicidal. The improvements to the cavity magnetron by John Randall and Harry Boot of Birmingham University in early 1940 marked

17420-406: Was read with an oscilloscope . When a pulse was sent from the broadcast towers, a visible line travelled horizontally across the screen very rapidly. The output from the receiver was amplified and fed into the vertical axis of the scope, so a return from an aircraft would deflect the beam upward. This formed a spike on the display, and the distance from the left side – measured with a small scale on

17554-410: Was taken, and then served as the 3rd Army's and eventually Wilhelm's headquarters. By 19 September the encirclement was complete, and the siege officially began. Responsible for the direction of the siege was General (later Field Marshal) Leonhard von Blumenthal . Prussia's chancellor Otto von Bismarck suggested shelling Paris to ensure the city's quick surrender and render all French efforts to free

17688-577: Was the first Royal Navy radar with a plan-position indicator . Further development led to the Type 277 radar , with almost 100 times the transmitter power. In addition to the microwave detection sets, Coales developed the Type 275 and Type 276 microwave fire-control sets. Magnetron refinements resulted in 3.2-cm (9.4-GHz) devices generating 25-kW peak power. These were used in the Type 262 fire-control radar and Type 268 target-indication and navigation radar. In 1922, A. Hoyt Taylor and Leo C. Young , then with

17822-427: Was the only means by which communications from the rest of France could reach the besieged city. A specially laid telegraph cable on the bed of the Seine had been discovered and cut by the Prussians on 27 September, couriers attempting to make their way through the German lines were almost all intercepted, and although other methods were tried, including attempts to use balloons, dogs, and message canisters floated down

17956-407: Was to assist attacks by torpedo boats by dazzling gun crews on the ships being attacked. Other uses included detecting enemy ships at greater distances, as signaling devices, and to assist landing parties. Searchlights were also used by battleships and other capital vessels to locate attacking torpedo boats and were installed on many coastal artillery batteries for aiding night combat. They saw use in

#800199